SRP A Multimedia Protocol Ken French George Oprica Mike Piecuch - - PDF document

SRP - A Multimedia Protocol 1

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SRP A Multimedia Protocol

Ken French George Oprica Mike Piecuch Advisor: Mark Claypool

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Multimedia Characteristics

Loss Latency

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Multimedia Over TCP

Guaranteed delivery (No loss) Flow Control Unbounded delay

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Multimedia Over UDP

Best effort delivery (minimal latency) Unbounded loss

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Multimedia Over SRP

Selective Retransmission Protocol Combination of TCP & UDP Retransmits a percentage of lost packets Application layer client/server protocol

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SRP Implementation

Algorithms Equal Loss Latency (ELL) Optimum Quality (OQ)

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Testing Approach

UDP blaster Token bucket router

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Sample Data

SRP - ELL (3% loss, 50ms) 50 100 150 200 250 1 51 101 151 201 251 301 351 401 451 501 551 601 Packet Number Latency (ms) 5 10 15 20 25 30 35 40 45 Lost Packets

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Low Loss, Low Latency

3% Loss , 50 ms Round Trip Time

0.2 0.4 0.6 0.8 1 1.2 1.4 0.2 0.4 0.6 0.8 1 1.2 1.4 Loss (normalized) Latency (normalized) SRP - ELL SRP - OQ UDP TCP

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High Loss, High Latency

15% Loss , 275 ms Round Trip Time

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0.5 1 1.5 2 Loss (normalized) Latency (normalized) SRP - ELL SRP - OQ UDP

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Conclusions

SRP is a good balance Great potential Additional tuning

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Future Work

Flow control Loss detection Additional algorithms